WO2022017541A1

WO2022017541A1 - Method for retaining and protection of foundation excavations under geological condition of soil layer containing stones

Info

Publication number: WO2022017541A1
Application number: PCT/CN2021/113859
Authority: WO
Inventors: 张丽; 潘中奇; 杨丽颖; 周蝾; 黎小红; 郝相如; 金泽康
Original assignee: 中国长江三峡集团有限公司; 北京市凉水河管理处
Priority date: 2020-11-20
Filing date: 2021-08-20
Publication date: 2022-01-27
Also published as: DE112021000151T5; CN112442991A; GB2605291B; JP2023501743A; JP7381747B2; GB202207292D0; CN112442991B; GB2605291A

Abstract

A method for retaining and protection of foundation excavations under the geological condition of a soil layer containing stones, the method comprising: S1, conducting geological exploration, and determining the position of stones on an excavating path of a foundation excavation; S2, measuring and positioning the boundary of the foundation excavation; S3, a drilling machine handling the stones along a foundation excavation retaining and protection boundary, wherein after the drilling machine firstly drills a plurality of large holes in a soil layer above the stones, protective tubes are inserted into the plurality of large holes respectively, then the drilling machine passes through the protective tubes to drill small holes in the stones, and next, a hydraulic splitting machine is inserted into the small holes, such that the hydraulic splitting machine is used to split the stones to form splits; and S4, performing surface earthwork excavating, installing steel purlins, and driving steel sheet piles. A retaining and protection structure comprises a plurality of insertion plates and connecting plates, wherein clamping slots corresponding to the insertion plates are provided on two sides of each connecting plate. The present invention is used for solving the problem of it not being possible for existing retaining and protection of foundation excavations under the geological condition of a soil layer containing stones to penetrate stones, and a plurality of working faces can be in operation at the same time, thereby shortening a construction period. Moreover, no pollution is caused to the environment.

Description

A method of foundation pit support under the geological condition of soil layer with rocks

technical field

The invention relates to a method for supporting a foundation pit under the geological condition of rock sandwiched in a soil layer.

Background technique

During the excavation and construction of new foundation pits, different types of foundation pit support structures are widely used, including I-beam pile support, Larsen steel sheet pile support, and cement mixing pile support. In the geological conditions where there are many large stones in the soil layer, the pile head of I-beam, Larsen pile or cement mixing pile cannot penetrate the stones. Blasting or crushing, over-excavation and replacement of filling and then driving of supporting piles, and then reverse grooving construction will not only cause a sharp increase in project investment and prolong construction period, but also easily cause safety accidents and affect surrounding roads or houses.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a method for foundation pit support under the geological conditions of the soil layer with stones, which is used to solve the problem that the existing foundation pit support cannot penetrate the stones under the geological conditions of the stones in the soil layer. , only blasting or crushing the stones, over excavating and replacing the filling, driving the supporting piles, and then reverse grooving construction, resulting in a sharp increase in project investment, prolonged construction period and impact on surrounding roads or houses.

In order to solve the above-mentioned problems, the technical scheme to be solved by the present invention is:

A method for foundation pit support under the geological condition of rock sandwiched in soil layer, comprising the following steps:

S1, geological exploration, to determine the position of the stones on the excavation path of the foundation pit;

S2, measure and locate the boundary of the foundation pit;

S3, the drilling machine processes the stones along the boundary of the foundation pit support;

S4, after setting the supporting structure in the borehole, excavate the surface soil, install the steel purlin and drive the steel sheet pile.

When performing the above step S3, drilling is required to pass through the stone.

The supporting structure includes a protective pipe, the protective pipe passes through a drilled hole, an I-beam is arranged in the protective pipe, and cement slurry is filled between the I-beam and the protective pipe.

In the above step S3, the drilling machine first drills a plurality of large holes in the soil layer above the stones, then inserts the protective pipes into the plurality of large holes, and then drills small holes on the stones through the protective pipes , and then insert the hydraulic splitting machine into the small hole, and use the hydraulic splitting machine to split the stone into a crack.

The supporting structure includes a plurality of plug-in boards and a connection board, and the two sides of the connection board are provided with card slots corresponding to the plug-in boards. The plate is inserted into the crack between the two adjacent protective pipes, and then the hydraulic splitter and the protective pipe are removed, and the connecting plate is inserted into the gap between the inserting plates.

The beneficial effects of the present invention are:

1. The project cost is low and the construction period is short. Using this method of foundation pit support, the project cost is reduced by at least 40% compared with the over-excavation, replacement, filling and reverse grooving process, and multiple working faces can be started at the same time, saving construction period and causing no pollution to the environment.

2. Small footprint, strong adaptability to surrounding terrain, and high safety. It is basically not restricted by the surrounding terrain and buildings, and it is safe to excavate after the foundation pit support is completed, and will not affect the surrounding roads and buildings.

3. After the support structure can be pulled out, the process of recycling can be realized, the utilization rate of resources can be improved, and the consumption of disposable materials can be minimized.

4. The spacing of the support structure can be adjusted according to the depth of the foundation pit, with strong adaptability.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings:

Fig. 1 is the top view structure schematic diagram of embodiment 1,

Fig. 2 is the front view structure schematic diagram of embodiment 1,

Fig. 3 is the top view structure schematic diagram of embodiment 2,

Fig. 4 is the front view partial sectional structure schematic diagram of Embodiment 2,

5 is a schematic diagram of a partial cross-sectional structure of Embodiment 2,

FIG. 6 is a partial top-view structural schematic diagram of Embodiment 2. FIG.

In the picture: steel sheet pile 1, protective pipe 2, I-beam 3, steel purlin 4, stone 5, connecting plate 6, insert plate 7, hydraulic splitting machine 8.

detailed description

S1, geological exploration, to determine the position of the stone 5 on the excavation path of the foundation pit;

S2, measure and lay out the boundary of the foundation pit;

S3, the drilling machine processes the stones 5 along the boundary of the foundation pit support;

S4 , after the supporting structure is set in the borehole, the surface soil is excavated, the steel purlin 4 is installed, and the steel sheet pile 1 is driven.

The two support structures are further described below:

Example 1:

When the thickness of the stone block 5 is less than 1m, the supporting structure composed of the PE protective pipe 2 and the I-beam 3 can be used. During implementation, as shown in Figures 1 and 2, the drilling machine drills through the stone block 5, and then drills through the stone block 5. Apply lubricating oil to the inner wall of the protective pipe 2, insert the protective pipe 2 into the drilled hole, place the I-beam 3 in the drilled hole, and fill the cement slurry between the I-beam 3 and the protective pipe 2. After the cement slurry is solidified , Excavate the earthwork or stonework about 50cm on the surface of the soil layer, install the steel purlin 4 and drive the steel sheet pile 1. After the excavation of the foundation pit is completed, pull out the PE protective pipe 2 and the I-beam 3 through the pile driver. Repeat use.

Example 2:

When the thickness of the stone block 5 is more than 1m, and it is difficult for the drilling rig to drill through the stone block 5, the supporting structure composed of multiple insert plates 7, connecting plates 6 and steel protection pipes 2 can be used. When implemented, as shown in Figures 5 and 6 As shown, the drilling machine first drills a large hole in the soil layer above the stone block 5, inserts the steel protective pipe 2 into the large hole, then drills a small hole on the stone block 5, and then inserts the hydraulic splitter 8 into the large hole. After entering the small hole, a plurality of hydraulic splitting machines 8 are used to split the stone 5 into a crack with a width of 2-3 cm, and the pile driver first inserts each plug board 7 into the crack between the two adjacent protective pipes 2. , and then remove the hydraulic splitter 8 and the protective pipe 2, insert the connecting plate 6 into the gap between the inserting plates 7, and require that both sides of the inserting plate 7 are located in the slot of the connecting plate 6, and the stone 5 and the soil layer will connect the inserting plate 7 After clamping and fixing, the pile driver will drive the steel sheet pile 1 and install the steel purlin 4 to complete the installation of the support around the foundation pit.

Claims

A method for foundation pit support under the geological condition of rock sandwiched in soil layer, is characterized in that, comprises the following steps:

S1, geological exploration, to determine the position of the stones (5) on the excavation path of the foundation pit;

S2, measure and locate the boundary of the foundation pit;

S3, the drilling machine processes the stones (5) along the boundary of the foundation pit support;

S4, after the supporting structure is set in the borehole, the surface soil is excavated, the steel purlin (4) is installed, and the steel sheet pile (1) is driven.
A method for foundation pit support under the geological condition of soil layer containing rocks according to claim 1, characterized in that, when the above-mentioned step S3 is performed, the drilling is required to pass through the rocks (5).
A method for foundation pit support under the geological condition of soil layer with rock blocks according to claim 2, characterized in that, the support structure comprises a protection pipe (2), and the protection pipe (2) passes through the borehole , an I-beam (3) is arranged in the protective pipe (2), and cement slurry is filled between the I-beam (3) and the protective pipe (2).
A method for foundation pit support under the geological condition of soil layer containing rocks according to claim 1, characterized in that, when performing the above step S3, the drilling machine first drills the soil layer above the rocks (5). After taking a plurality of large holes, insert the protective pipe (2) into the plurality of large holes respectively, and then drill small holes on the stone (5) through the protective pipe (2), and then connect the hydraulic splitter (8). ) is inserted into the small hole, and a hydraulic splitter (8) is used to split the stone (5) into a crack.
A method for foundation pit support under the geological condition of rock sandwiched in soil layer according to claim 4, characterized in that, the support structure comprises a plurality of plug-in plates (7) and connecting plates (6), and the connecting plates (6) are connected to each other. The two sides of the plate (6) are provided with card slots corresponding to the insert plates (7). ) into the crack between two adjacent protective pipes (2), then remove the hydraulic splitter (8) and the protective pipe (2), and insert the connecting plate (6) into the gap between the inserting plates (7).